Remove objects moving towards camera while zooming out?

Hey everyone

Im using Mocha Standalone Learning Edition!
Currently trying to get better at complex object removals to prepare for an upcoming project.

Topic is about this shot:

Task is to remove the 3 Biker Girls. Is this even possible?

I cant wrap my head around how the proper workflow for a shot like this would look like, maybe im heading in the wrong direction…

What i did so far is track all 3 Bikes in the right order (according to Remove Module Tutorials i found).
And that worked more or less.

But now i wanted to track the background (essential for the remove module to work) but came to realize, that there is too much parallax. I cant even get to track the street only.

Any ideas? Is this even possible with a ridiculous shot like this?

Thanks in advance :slight_smile:


That is for sure a very difficult shot to cleanup. Not impossible, but I would think you would really struggle to get accurate results for the entire shot with the Mocha Remove module alone.
You may be able to get more help from other users on here with using the Remove Module for sections of this but I’ll briefly try to explain how I would approach a big paint shot like this.

First thing I would ask is do you have a cleanplate as that would save having to manually paint the BG and pull from different frames to rebuild all the different sections. You’d also probably want to stabilize the camera, a full 3D camera would be ideal with tracked geo available to use for projecting onto the road etc. Shots like this are 200% harder & longer without a tracked camera.
If none of this is available then first I would ask are they paying you enough! If they are then you are going to need to first track the shot yourself & then separate everything into layers and essentially rebuild everything separately. Separating all the trees & foliage is a tricky task, a fair bit of roto will be required but soft fractal blurs & warps to ‘fake’ parralax can also be a very handy trick in this situation.

The road is also pretty difficult to rebuild due to the amount of backwards movement in depth. The traditional way would be to make one huge patch from lots of different frames probably in some form of UV projection onto geo. You could have a look at Mocha’s new Mega Plates feature which essentially aims to achieve the same thing of creating one huge patch from data across the entire frame range, it most probably won’t get you there straight away but it might be very good starting point.

Cleanup shots like this also depend on what is supposed to be happening on this shot. Is there going to be a CG explosion where a large majority of the plate is covered in smoke and dust? Or is the shot going to be completely empty with nothing but the background? That will really affect how much detail your cleanup work needs to be.

Sorry this post is still quite brief but hopefully some of it helps understand what you might need to do here. I’d be happy to help further if needed.

Thank you for taking your time to write this detailled reply.

For now the task is to empty it as good as possible.
Eventually the plan is to track Bike Girl 1 and replace her with some sort of 3D vehicle.

How exactly would a cleanplate for this look like? Wouldnt it have to be a megaplate as you mentioned? Are you referring to a still image- or a movie - plate?

Thats a great idea! I will try to do a 3D Solve for this scene and overlay basic geometry in C4D. In theory i could then create a plate from the video (stichted together from different frames like you said) that i project onto the road geometry.

I suppose it would be much harder for the trees though.

An ideal cleanplate for this would be seperate footage shot on location that matches the sourceplate as close as possible but just without the FG elements. Obviously the camera movement wouldn’t be exact unless you use a motion controlled rig. You can get cleanplates from witness cams or reference plates or even still photography of the set would be salvagable but anything useable would need to have been shot at the same time as the main sourceplate so all the lighting matches etc. If the cleanplates are not very good often it can be more work to make them useable anyway so I wouldn’t worry too much about them if you don’t have any available. You will most likely want to rebuild the BG from other frames first & good cloning for any areas that are never visible.

I just wanted to add, that while this is not impossible to do in Mocha with the remove helping you, but you’re still looking at a lot of hand fixes because of the trees and weeds, which never stay nice and still and show a lot of parallax between branches. You might be able to get away with feathering the shapes but probably not. the above advice is sound. Either way, you won’t be able to track one plane and be done with it. You’d need to track every plane moving behind them, road, trees, wall, weeds, bg car, etc. That’s essentially a camera solve at that point anyway and a camera solve might be easier.